A quick rummage around a typical gardener's shed will uncover various forms of derris, the well-known organic insecticide - but all that is set to change next year with the proposed outlawing of the product.Horticulturist Martin Fiddes explains...

Rotenone - the active ingredient obtained from the crushed root of the derris tree - has been linked to the progressive brain disorder Parkinson's disease, and a subsequent investigation by the Pesticide Safety Directive (PSD) has led to the decision to withdraw all derris-based sprays and powders.Although no definitive date has been set for the removal of derris from the market, sources claim that products will be available until September 2009. This will give organic gardeners plenty of time to find new artillery for the constant battle against garden pests such as aphids, caterpillars and flea beetles.

Among the products to be targeted are Liquid Derris and Derris Dust, but organic alternatives do already exist in the shape of sprays containing fatty acids, plant oils and pyrethrums. Derris itself has been used in the amateur horticultural sector since the mid-19th Century.

According to NHS statistics, Parkinson's disease afflicts up to 120,000 people in the UK and some high-profile celebrities, such as ex-world heavyweight boxing champion Muhammad Ali and Hollywood actor Michael J Fox.